A female Sacculina carcini larva – crab hacker barnacle -set…

A female Sacculina carcini larva – crab hacker barnacle -settles on a suitable crab host and inhibits the development of the crab’s gonads, which eventually atrophy. The parasite causes a male crab to develop certain feminine characteristics including the broadening of its abdomen. In females crabs, the abdomen becomes narrower and the pleopods degenerate. Both male and female crabs become sterile. The eggs of the parasite develop and both male and female crabs carry these eggs around, secured under their abdomen, in the way that female crabs normally care for their own brood.  What is described here is an example of:

In which stage is the vaccine given to groups of fewer than…

In which stage is the vaccine given to groups of fewer than a hundred volunteers? This is when researchers discover if the candidate actually produces enough of an immune response in a human that it would make sense to move forward with a bigger study. It also tests to see if there are any serious and significant side effects. This is also used to establish a safe dose for the vaccine.